Oh lord, it's the other way around...the things that so many people think that they themselves can't understand....it's frustrating beyond words too many times. It's reverse-snobbery. The assumption that I cannot possibly understand X because it's not my profession, C'mon people...
I think both happen. I'm guessing, but the root of it is people don't want to think outside their box, because then they'd have to look at the whole. If you apply "be true to yourself so as to be true to the world" (reversed), you end with they'd have to look at themselves. Which is why we live on the surface, to avoid that.